1. Field of the Invention
The present invention relates to an edge sewing apparatus for sewing an edge of a cloth piece in a strip-like shape along one side edge thereof in a curved shape.
2. Description of the Related Art
Conventionally, one corner portion of a cloth piece in a strip-like shape such as a fly of a jeans or an ordinary pants or the like is cut in a circular arc shape and edge sewing is carried out along a circular arc edge portion. In this edge sewing, normally, a sewing operator sews the edge while manually rotating the strip-like cloth piece centering on one end portion thereof, without using an exclusive sewing machine. However, according to the manual operation of rotating the strip-like shape cloth piece, by a difference in the technique among the sewing operators, not only an influence is effected on a production amount but also a difference is liable to be brought about in quality thereof.
In order to avoid the difference, there has been developed an edge sewing apparatus of carrying out edge sewing in a circular arc shape by rotating a cloth piece by utilizing a cloth feeding mechanism of a sewing machine by pressing one point of the cloth piece by moving a cylinder up and down and thereafter continuing the edge sewing in a linear shape. Such an edge sewing apparatus is disclosed in, for example, JP-B-7-28970. A strip-like cloth piece is fed skewedly to a cutting blade arranged at the edge sewing apparatus. When sewing is started under this state, the cloth piece is fed forward along a cloth feeding direction by a cloth feeding mechanism of an edge sewing portion while cutting a cloth end by the cutting blade. When the cloth piece is fed forward in this way, the cylinder is operated and one corner portion of a front side of the cloth piece is pressed by a ball. Therefore, the cloth piece is rotated centering on the ball by the cloth feeding mechanism for feeding the cloth piece in one direction. In accordance with the rotation, the one corner portion of the cloth piece is cut in a circular arc shape by the cloth cutting blade. Thereafter, edge sewing is carried out along the circular arc shape edge portion.
Further, according to the technique disclosed in JP-B-7-28970, in starting to rotate the one corner portion of the cloth piece, when a side end face on one side of the cloth piece is deviated from a cloth side end detecting sensor, a signal is generated from the cloth side end detecting sensor. The cylinder is then operated by the signal and the ball presses an upper face of the one corner portion of the cloth piece. When pressing by the ball is operated, by cloth feeding by the cloth feeding mechanism, the cloth piece is rotated centering on the pressing point of the ball. Then, the cloth piece is moved in a direction of making the side end face on one side of the cloth piece deviated from the cloth side end detecting sensor to be proximate to the cloth side end detecting sensor. When the side end face on one side of the cloth piece covers the cloth side end detecting sensor, operation of the cylinder is released by a detecting signal thereof to separate the ball upward from the upper face of the cloth piece. When edge sewing in the circular arc shape is carried out by a predetermined amount in this way, the cloth piece is guided on a linear line along a side end of the cloth piece to carry out edge sewing of a linearly sewing portion. That is, according to the edge sewing apparatus, the cloth piece is pressed by the point, the cloth piece is rotated centering on the point, the end portion of the cloth piece is detected by the detector and it is detected whether the cloth piece is rotated to a predetermined position.